Protective device



W. J. STANTON PROTECTIVE DEVICE Filed March 27. 1929 June16, 1931.

Inuen or Millard 115131112111 Patented June 16, 1931 uurran STATESWILLARD J. STANTON, OF CHICAGO, ILLINOIS, ASSIGNOR, BY HESNEASSIGNMENTS, TO

AMERICAN ELECTRIC COMPANY, INC., OF

DELAWARE CHICAGO, ILmNors, A CORPORATION 01* PROTECTIVE DEVICEApplication filed March'27, 1929. Serial No. 350,245.

My invention relates to protective devices in general, but,moreparticularly it pertains to protective devicesof'the character used toprotect the user of a telephone instrument from high potential currentswhich might be induced into the telephone line from nearby power lines.

I have assumed as the principal object of m my invention the provisionof a telephone protective device which cannot fail to function properlyand which is readily adapted for use with almost any make of a telephoneinstrument. a

, The "principal features and other objects 15 will be apparent from thedescription of the construction and adaption of the deviceof myinvention when taken inconj unction with the single sheet of drawings inwhich 20 Fig. 1 is a perspective view of the protective device with thecover of the encasing box removed and enough of the side broken away togive a clear viewof its contents;

Fig. 2 is a diagrammatic representation of a telephone line and theprotective device combined; and 3 c i Fig. 3 is a ,plan view of amodification of my invention.

A detailed description will first be given of m the construction'of theprotective device, reference being had particularly to Fig. '1.

Reference numeral 1 designates a telephone instrument of the type whichmounts on the wall. The telephone has been shown inpartial outline only,since instruments of that type are well known. The telephone 1 has theusual receiver 2' and receiver hook 3. Attached in any suitable mannerto the side of the telephone 1 is the protective device 40 which isassembled in the metal box 4. This box is lined with thin sheets ofinsulating material 5. In the top of the box there are shown six holeswhich are bushed by the bushings 6 of insulating material. Through theseholes the various conductors of theline, the arresters and the telephoneinstrument enter the box where they are terminated in the connectinglugs The lugs 8 are on a block of insulatingmaterial 7. which is locatednear the top of the box. i v

Centrally located in the box and fastened to the back thereof,'butinside, is'the bracket9 which is substantially U-shaped. The ends 10 and:11 of this bracket have holes therein, in which the shaft 12 slides-Fastened by means of screws to the end 10 of bracket 9 is a block 13 ofinsulating material. The block 13 is provided with slots into which areforce-fitted the contact springs 14, 15, 16, 17 18 and 19, theu'pper'ends of which are formed into tagsto which the jumper wiresconnectingthem with lugs 8 may be soldered. Those springs are madeeasily accessible for replacement by the removable strips of insulatingmaterial 20 and 21 which'are fastened to block 13 by means of screws.

Rigidly fastened to shaft 12 by means of a screw 23 is another block ofinsulating ma.- terial 22. A helical spring 24 about the shaft 12 andabutting the blocks 13 and 22, forces block 22 and shaft 12 downwardsuntil block 22 stops up against arm 11-of bracket 9. Gontact members 25and 26 are fastened to the ends of block22 by screws such as 27;. One ofthe screws 27 which fastens member 25 projects into block 22 until itthreads into contacting member 28 which fits into a slot" in block 22.Members 25 -and28 are thereby conductively connected together. In asimilar'manner, contacting member 29, which also fits intoa'slot inblock 22, is conductively connected to member 26. It will be noted thatmembers 28 and 29 "do not project as far above the uppersur-faceof block22 as do members 25 and 26. The reason for that arrangement will beexplained subsequently. I

' Mounted on the inside back of the box 4 and perpendicular to bracket 9is another bracket 30. Theen'ds 31 and 32 of bracket are provided withholes in which the rod 33 may slide. The right hand end of rod 33 isslotted and the extremity is provided with the screw cap 34 ofinsulating material which projects through the front side of the box. Apin 35 projects through the slot in rod 33 and a pin 36 projects througha slot in the lower end of shaft 12. A post 37 fastened to the base, orback, of the box 4, carries the V-shaped rocker arm 39 which ispivotally mounted on the post 37 by means of screw 38. The arms 40 and41 of the member 39 are slotted to receive the pins 36 and 35,respectively, when the arms are inserted in the slots in shaft 12 androd 33, respectively. Thus the slots in the arms 40 and 41 and the pins36 and form sliding pivots. The member 39 prevents the shaft 12 and therod 33 from rotating in the brackets 9 and 30.

It can now readily be seen that if the cap 34 is pressed into the box,the rod 33 will move to the left, imparting a clockwise rotation tomember 39 which through the action of arms 41 and 40 lifts the shaft 12and the block 22 carried thereby. against the tension of spring 24. Whenthis takes place, the contacting members 25 and 26 engage contactsprings 18 and 19, and 14 and 15, respectively. Further lifting of theshaft 1.2 causes contacting members 28 and 29 to engage contact springs17 and 16, respectively, after the other members have engaged the othersprings.

In this manner, the outside line conductors, fastened to springs 15 and18, are first grounded through carbon arresters connected to springs 14and 19, before the line connected to the line conductors of the telephone instrument which are connected to springs 16 and 17.

The spring 24 restores the mechanism to normal when pressure is removedfrom the cap 34.

Attached to the rod 33 by means of screws is a flat piece of steel 42which projects through a slot in the box 4 as shown. 11t tached to theoutside of box 4 is a right angle bracket 43 to which. is pivotallyfastened the forked member 44. The bracket 43 and member 44 are sopositioned that the receiver hook fits between the prongs of the fork.Movement of the receiver hook up and down rotates the member 44 ack andforth about its pivot hen the receiver hook is down, and th equipment inthe box is in nor mal, the piece 42 is in position above the upper prongof the member 44 so that the receiver hook cannot be moved upwardwithout first pressing the cap 34 to move the piece 42 to the left. Theupper prong of the member is provided with a step 46. hen the member 42is moved to the left of the vertical edge of this step, the book 3 maymove upward. If the pressure is released from cap 4 after the upwardmovement of the hook, the member 42 presses against the vertical edge ofthe step 46 and is held there, thereby holding the members carried byblock 22 in engagement with the contact springs.

The amount of movement of member 42 to the left necessary before step 46is reached is enough to prevent upward movement of the hook 3 untilmembers 25 and 26 have engaged their respective contact springs. In thismanner, it is assured that the outside line is first connected to thearresters before the 1 receiver hook is allowed to move to operate theusual receiver hook springs within the telephone instrument whichcontrol the local circuits of the instrument.

When the receiver is placed upon the hook, the weight thereof pulls downthe receiver hook and thereby releases the eql'iii unent, allowing themember 42 to slide over the membe 44 to lock the hook in position.

In Fig. 2 the parts of the equipment of Fig. 1 shown therein, areninnbered to correspond with parts in Fig. 1.

The lines to which the telephone has access are terminated in the fusebe): and then iumpered to the act: box. The person desiring to use thetelephone selects the desired line by inserting the dunnny plug P intothe proper jack. Assuming that the line comrsis conductors 4'? and 48 isthe desired D the insertion of plug P into the uppc gack connectsconductors 4T and 48 with line conductors 49 and 50. respectively. Theuser of the telephone now removes the receiver from the hook and pressesthe cap 34. If desi 1 l, the receiver may be left on the hook until thecap 34 has been pressed. .Vhen member 44 has been freed by the movementof piece 42 to the left, the receiver hook and the free ends of themember 44 move upward under the inthiencc of the usual hook springswithin the telephone instrun'ient. Shaft 12 moved upward as has beenexplained causing contacting inen'ibers and to engage the springs 13 and19, and 14 and 1", respectively. Gonductors 49 and 50 are therebyconnected to ground by wa of the arrester and conductors 52 and 53.Further move ment of shaft 12 causes contacting members and 29 to engagesprings 17 and 16, respectively, thereby connecting the line conductors49 and 50 to the conductors 54 and 55, respectively, which lead to thetelephone instrument. The user of the telephone may now proceed toestablish the desired connection in accordance with the type oftelephone system.

rom the foregoing it can be seen that I have provided a protectivedevice which cannot fail in its operation so that the user of atelephone instrument in cases where the telephone line is in closeproximity to high potential power lines is fully protected from high.potential currents induced in the telephone line by making the telephoneinstrument unavailable for use until after the line has first beengrounded through arresters be fore it is connected to the telephoneinstrument. It will be noted that the arrester is only in use as long asthe telephone instrument is in use.

An extra precaution may be taken by tying the receiver cord to theswitchhook so that if the receiver is dropped or left off the book, heweight of the receiver will pull down the hook and release theprotective cut-off equipment as has been explained.

No means has been shown for signalling this telephone station for it isassumed that this station is only for outgoing calls and might be a.station such as located along the right-of-way of a railroad.

A modification of the invention which is also readily adaptable will nowbe briefly explained, it being shown in Fig. 3 of the drawings.

In the modification, the box 4: holding the equipment is not attached tothe telephone but is installed in a separate steel box upon the floor ofthe telephone booth. The equipment in the box is operated by a footpedal. In that case, the piece 42, the bracket 43 and member ii are leftoif of the equipment. Pressure on the foot pedal operates the rod 33 asif the telephone user had pressed with his thumb on the cap 34L.However, it is necessary to maintain pressure on the foot pedal as longas the telephone is in use. Removal of pressure from the foot pedalallows the equipment to restore to normal.

Having thus described my invention, what I consider new and desire tohave protected by Letters Patent is pointed out in the appended claims:7

1. In a telephone system having a line and arresters, the combination ofa telephone, and means for preventing the mechanical operation of saidtelephone until after said line has been connected to said arresters.

2. In a telephone system, the combination of a telephone, a telephoneline,-and means for connecting said line to arresters and for connectingsaid line to said telephone, said means preventing the mechanicaloperation of said telephone until said line has been connected to thearresters.

3. In a telephone system, the combination of a telephone having areceiver hook, a telephone line, an arrester, and means for connectingsaid line to said arrester and then connecting said line to saidtelephone, said means preventing the operation of said hook until saidline has been connected to said arrester.

4. In a telephone system, a line, an arrester,

, a telephone having a receiver'hook, a protective device for saidtelephone,

and then connecting said line to said telephone,

said receiver hook in inoperative position until said line has beenconnected to said arrester.

5. In a telephone system, a line, an arrester, a subscribers telephonehaving a receiver hook, a protective device for said telephone,

means in said device for connecting said line to said arrester and forthen connecting said means in said device for connecting sa1d line tosa1d arrester and means in said device for locking maintaining saidconnections until said hook is returned to normal.

6. In a telephone system, a line, a subscribers telephone having areceiver hook, a pushbutton switch for connecting the telephone to theline, and means controlled by said hook for locking said switch in itsoperated position to maintain said connection while the receiver is offthe hook and for releasing said switch and said connection when thereceiver is replaced on the hook.

7 In a telephone system, a line,an arrester, a subscribers telephonehaving a receiver hook, a push-button switch for connecting said line tosaid arrester and then connecting said line to said telephone, and meanscontrolled by said hook :tor locking said switch in operated position tomaintain said connections while the receiver is off the hook, said meanseffective upon the replacement of the receiver upon the hook forreleasing said switch and said connections.

8. In a telephone system, a line, arresters, a subscribers telephone,connecting means, and means operated by the subscriber for operatingsaid connecting means to first connect said line to said arresters andto then connect said line to said telephone.

9. In a telephone system, a line, arresters, a subscribers telephonehaving a receiver hook, connecting means, means operated by thesubscriber for operating said connecting means to first connect saidline to said arresters and then connect said line to said telephone, andmeans operated by said hook responsive to the removal of the receivertherefrom for maintaining said subscriber-operated means and saidconnecting means operated to maintain said connections.

In witness whereof, I hereunto subscribe my name this 25th day of March,A. D. 1929.

" WILLARD J. STANTON.

